1. Field of Invention
The present invention discloses a method and apparatus for venting containers sealed by a bung, such as containers of the type commonly used to store and transport hazardous materials. The invention in particular pertains to a method and portable apparatus for remotely loosening the bung on a potentially over-pressurized container, thereby safely relieving excess pressure in the container thereby potentially avoiding a container rupture.
2. Description of Related Art
Containers, usually made from steel or plastic and having capacities ranging from 30 to 85 gallons, have long been used to transport and/or store a variety of commercial primary and waste products. These containers provide a tightly sealed container and are therefore well suited for storing and for transporting hazardous wastes and other reactive liquid chemical products.
Containers containing hazardous materials must be kept tightly sealed for transportation and storage in order to reduce the risk of accidental spillage and contamination of facilities and the consequent risk to hazardous materials handling personnel. When these sealed containers are heated, either through exposure to catastrophic accident conditions such as fires, or simply through normal weather-related environmental heating, the pressure in the containers can rise. Over-pressurization can also result from unanticipated chemical reactions occurring inside the container. Over-pressurization of containers can cause catastrophic failure in the container. Numerous incidents of fire, explosion, and ground contamination have occurred at various facilities over the last several years due to container rupture caused by over-pressurization events.
When a container becomes over-pressurized, the walls of the container, including the top and bottom panels, will often be deformed by the internal pressure buildup. It is desirable, in over-pressurization events, to loosen the container bung or to puncture the upper container panel in order to release the pressure prior to a catastrophic failure of the container walls. When the over-pressurization is caused or exacerbated by ongoing chemical reactions in the container it is particularly important to release the pressure as soon as possible. When the container contains hazardous materials, however, releasing the pressure becomes problematic and potentially hazardous. The rapid release of pressure and expulsion of gasses from the container during depressurization may cause a quantity of the container contents to spray out of the container, posing a hazard to any person in the immediate vicinity. Also, the pressure build up and container panel deformation may be sufficient to cause the bung cap to be ejected from the container with sufficient momentum to present a hazard to any worker in the area. Moving the container to a different location without depressurization, on the other hand, increases the risk that the pressure and/or stresses associated with transportation will generate sufficient force to rupture the container and increases the time before the pressure is released, further increasing the risk of catastrophic failure of the container.
Similar hazards are present when Hazardous Materials Response Teams (HazMat Teams) are called upon to deal with hazardous waste and materials storage facilities or abandoned or discarded container sites. Some of theses containers may be very dangerous to deal with due to container deterioration resulting from age and exposure to the elements, pressure build-up inside the container, and potentially unknown hazardous materials contained in the containers.
Current technologies in the field offer few solutions to these problems. The most commonly used method of handling containers of this nature is to simply vent the container manually, either by loosening the container bung with a bung wrench such as those described in U.S. Pat. No. 654,858 or U.S. Pat. No. 2,643,566, or by puncturing the container with some type of hand-held apparatus. While these methods offer the advantages of rapid container venting and requiring only a single worker to be exposed to danger, the individual worker executing this method may be subjected to released chemicals upon venting the containers, or may be injured, dismembered, or killed due to bung cap ejection or potentially by an explosion of unstable chemicals inside the container.
Another approach to this problem is typified by the Portable Remote Drum Opening Device disclosed by Haywood in U.S. Pat. No. 5,349,755 wherein a power-driven venting system, powered either by air or electricity, is installed onto an over-pressurized container which either drives a punch to pierce the head of the container, or turns a bung socket to loosen the container bung. These types of system, however, typically are expensive to own, require two or more persons to operate, and require a nearby power source for operation. Due to the high cost of such systems, they will frequently not be available at remote locations. Moreover, the use of electricity may present a risk of sparks igniting potentially flammable gases vented from the container.
A portable, hand-held device for remotely venting a container has been disclosed by Vodila et al. in U.S. Pat. No. 5,634,484. The disclosed device is apparently attached to a container, with a downwardly-projecting shaft terminating with a bung wrench. A second shaft engages the first shaft with a set of matching gears, such that rotation of the second shaft causes rotation of the first shaft and bung wrench. While this tool provides a helpful, albeit short, distance between the operator and the container bung, the operator still must remain in fairly close proximity to the bung. Also, no leverage is provided to facilitate bung removal. Moreover, the disclosed invention would not accommodate a bung that has been displaced a significant amount from the horizontal design condition, as is frequently the case in over-pressurization events wherein internal pressure deforms the container head.
Whatever method is used to vent the container. It is common for container over-pressurization events to result in the mobilization of several levels of emergency response teams at considerable cost and disruption.
There is a need for a simple, portable non-powered tool that will permit containers containing hazardous materials to be vented remotely and in situ prior to pressure in the container building up to levels sufficient to rupture the container. The disclosed invention is an article of manufacture designed to allow a single operator to vent an over-pressurized container from a safe distance, thus reducing the risk of injury to personnel on account of bung cap ejection, explosion, or inadvertent contact with harmful chemicals.
It is an object of the present invention to provide a portable apparatus for remotely venting a container having a bung, comprising a means for attaching the apparatus to the container, a support structure connected to the attachment means that extends over the top of the container, a bung wrench rotatably connected to the support structure in a position to engage the bung, an extension arm rigidly attached to the bung wrench, and an elongated member attached to the extension arm, whereby a user can rotate the bung from a safe distance by pulling on the elongated member.
It is a further object of the present invention to provide such apparatus wherein the bung wrench is made from a non-sparking metal such as aluminum or bronze.
It is a further object of the present invention to provide such apparatus wherein the angular position of the bung wrench with respect to the bung on the container may be adjusted.
It is a further object of the present invention to provide such apparatus that may be attached and operated by a single individual.
It is a further object of the present invention to provide a means to make multiple turns of the bung from a safe distance by incorporation of a rachet into the apparatus.
These and such other objects of the invention as will become evident from the disclosure below are met by the invention disclosed herein. In addition to the explicitly claimed method and apparatus described herein, as such, it is to be understood that all new and useful devices or components described herein are considered to constitute a part of the invention, claimable in their own right, whether such is stated with particularity herein or not.